lasthour=$(date +"%Y%m%d%H%M")
newhour=$(date +"%Y%m%d%H%M")
while test $newhour = $lasthour
do echo "  new hour = $newhour"
    sleep 1
    newhour=$(date +"%Y%m%d%H%M")
done
echo "hour changed:"
echo "  last hour = $lasthour"
echo "  new  hour = $newhour"